A welder’s arc caused an explosion in the stern cabin

(1) Accident process
Two oil workers at a shipyard were spraying the last coat of paint in a closed stern cabin. The painting work was completed at noon. When leaving the stern cabin, they left the manhole cover half open and half closed. There were no danger signs around the hatch cover (such as the cabin had been painted and fire could not be approached). At around 3 pm, a riveter came on board to install a small engine base. His work position was close to the stern cabin. When igniting the gas cutting, the riveter found that he did not bring an electronic lighter, so he asked the welder to help ignite the fire. The welder picked up the welding clamp and struck an arc on the stern cabin cover. Then there was a loud bang and the stern cabin exploded. 8 people died on the spot and 6 were injured.

(2) Analysis of the main causes
① The combustible gas of benzene in the paint mixed with air reached the explosion limit. In addition, the hot weather exacerbated the concentration of the combustible gas of benzene, so it exploded immediately when it encountered fire.
② After the stern tank was painted, no warning signs and guardians were set up.
③ No ventilation measures were taken in the stern tank after painting.

(3) Main preventive measures
① Warning signs and guardians should be set up around the tank.
② Compressed air should be passed through the stern tank to reduce the concentration of combustible gases.
③ When the welder strikes the arc, he should pay attention to the surrounding environment (i.e. flammable and explosive materials).